Singlepower ES1/ES2 Servicing Information and Questions
Jun 22, 2009 at 10:02 PM Thread Starter Post #1 of 16


Headphoneus Supremus
Jun 10, 2004
Hey guys,

So my Singlepower ES-2 developed a problem shortly after it arrived back from the International Meet. I don't think any of the issues had to do with its transportation, but rather something that was probably going to happen sooner or later.

The issue which has developed is the same that I originally encountered and had sent back to Mikhail. It was the delay in receiving this amp back that had originally prompted me to start:

Anyway, the issue is that the left channel went 'out'. The biasing for the left channel is uncontrollable (output and primary) and the volume is very low/almost non-existent.

I've located a high-end repairman/technician in Campbell, CA. The company is called True Sound. Thanks to foo_me for the contact.

So what Nick at True Sound will be able to do is a kind of 'Audit' so to speak of the amp. Since he will be the only other person to view the internals of this amp other than Mikhail himself, he will be able to verify from another perspective, if this amp measures up to what was originally sold to me. I have given him the original spreadsheet with all the specifications (including all the electronics, etc...).

*One question he had which I was not able to answer was about the biasing circuit in the amp. If anyone can help me with this that would be much appreciated. The amp has a built in bias meter and it has 8 buttons for measuring the bias:

Right Output (2 buttons)
Right Primary (2 buttons)
Left Output (2 buttons)
Left Primary (2 buttons)

The way I would go about biasing this amp was to press down these two buttons (primary or output for each side) and dial in the reading to as close to 000.0 as I could get. Nikongod helped me out with this at the International when I didn't have the bias display power adapter.

What Nick and I would like to know is what the reasoning is behind this. What is Primary, what is Output (on a technical level) and how is it measured. Also, why are there two buttons for each. If I hold down one, it gives me a reading sometimes but it's not right. I was told by Mikhail to hold both. It makes a scratching sound on the headphone when these buttons are pressed although as far as I know, they only read the bias, the knobs (Rt Primary. Rt Output/Lft Primary. Lft Output) still have to be turned.

Any info would be great if known.

Thanks! Hopefully Nick will be able to shed some additional light on the layout, and safety of the amp as well.

Jun 25, 2009 at 5:20 PM Post #2 of 16
I have the mind to very publicly go into detail as to what Kevin Gilmore, Spritzer, Nick (from True Sound), and I have been learning about our amps. VERY disappointing information to say the least. It's one thing to not have received your amp. But once you did... I wonder now if we are in an even worse position.

Jun 25, 2009 at 6:13 PM Post #4 of 16
I'll post pics and have some other information up as soon as I get time. Ideally some of the other guys would chime in who are more knowledgeable. Alternatively we might just set up links to 'another' site where people can follow the thread.

Jun 26, 2009 at 8:36 PM Post #7 of 16
As some of you might know Afrikane generously gave me his ES-1 so that I could tear it down, have the schematics drawn and find a way to fix these amps without involving Mikhail in any way. I will start a seperate thread later on where I will document what I found and how I set about rectifying it but lets just say that what I found was beyond bad build quality (dangerous even) and there are a lot of "upgrades" missing which were fully paid for. This seems to be a common thing with ES amps.
Jun 26, 2009 at 10:33 PM Post #8 of 16
what i don't get is that for years people said the SP amps were the best sounding amps out there. but now people are taking apart the very same amps and are saying that the build quality, parts used, and design are horrible. so how it is that they ever sounded good? either the amps never sounded good and people just thought they did because they were expensive and supposedly built with top of the line parts by a "master" builder or they did sound good and people are overstating the idea of "good"/"bad" design.

the whole SP debacle has reinforced my belief that all statements, regardless of whom they are from, should be taken with a grain of salt.
Jun 26, 2009 at 10:47 PM Post #9 of 16
What you fail to understand is that well built and boutique parts do not always equal great sound. There are plenty of examples of beloved products that were built poorly but perform well when they aren't broken. Several British and Italian cars come to mind as do early Vox amps.
Also super reliable and good parts can also yeild mediocre performance. Build quality is one part but there are other factors.
Jun 26, 2009 at 11:51 PM Post #10 of 16
Read HF for 5 minutes and you see people gushing over products so horribly designed that it's almost criminal yet they are accepted as being brilliant. When you don't know any better then it's hard to distinguish bad from good.

I don't doubt that many like the way SP amps sound but a few of us have had grave concerns over SP amps for quite a while now. You can just ask Jude since he closed down a thread I posted last fall listing all these issues with the ES amps. I'm not blaming him though since I assume Mikhail contacted him saying I was full of crap and since my sources at the time were pictures I couldn't distribute freely I had a hard time defending my point. Now that I have an SP ES-1 here in the flesh and access to detailed pictures of quite a few others it has become apparent just how messed up these amps are and how negligent Mikhail really is, ignoring even the most basic safety precautions. This applies to every type of amp he's even made, from the cheapest to the most expensive.
Jun 27, 2009 at 12:45 AM Post #11 of 16
As a former Jaguar owner i can agree with the above in spades.
I could go on and write a book about the blatant design flaws on
this car. But when it did run boy was it a lot of fun. I like the corvette
much more, its now almost 3 years old, and no matter how hard i try
i can't break it. And it has only half the number of parts the jaguar has.
Maybe the new jaguar owners will clean house.

I've always liked the sound of the SP extreme. There are ways to
make it reliable without changing the sound even the smallest little bit.
Try and find a balanced point to point wired unit and you will be very happy.
(replace the sockets and physically check every single solder joint)

The ES1/2 have a very well known sound signature that goes way back
to the early 1960's. There are ways to make these things reliable too.
without changing the sound even the smallest little bit.

I've seen spritzers pictures. I'm sure he will post them himself. Schematics
of the before and after are available. Future upgrades of the power supply
to a dual tracking shunt regulated supply will happen for sure.

Given the current situation as it is, and the number of units that have failed
recently, there has to be a way for the owners of these things many of whom
have spent significantly north of $14k to get the things fixed.

The technicians that touch these things need a pretty good understanding of
what is going on before they get in over their heads. It may be a very simple
schematic. Repairing them is not so simple.
Jun 27, 2009 at 1:26 AM Post #12 of 16
As I've learned the hard way, Singlehour isn't very reliable (at least mine wasn't). Right Mr Gilmore?
Jun 27, 2009 at 12:28 PM Post #13 of 16

Originally Posted by moonboy403 /img/forum/go_quote.gif
As I've learned the hard way, Singlehour isn't very reliable (at least mine wasn't). Right Mr Gilmore?

Picture of the transformer shown to all worth 1000 words.
In this case much more...

Do it. I can't do it for you.

Elephas has now published pictures on his amp, ask him for the link...
(47 megabytes compressed)
Jun 28, 2009 at 8:05 PM Post #14 of 16
At this point what is more important to me than even going into all the gory details (and there are many), is a way that all owners of these amps, who may find this product has suddenly failed, can have access to a known and simplified route to examine and fix them. This includes access to individuals knowledgeable enough and willing to fix them.

My tech at true sound feels that doing work on this amp would be out of scope for his business. He feels the overall design is flawed enough that a redesign would be in order. They are a repair shop, not amp builders. Anyway, even if I somehow force them into this route, it seems it would be cost prohibitive - with uncertain sonic results. I am hoping to figure out another solution.

In my case specifically, a replacement PSU with some fixes to the Amp itself will go a long way. I believe the Amp is salvageable whereas the PSU doesn't seem to share that fortune. Ideally, the new PS would be built into the existing case.

I'm sure more details will unfold as our 'in-house" gurus on this subject can make some headway here.

Jun 28, 2009 at 11:38 PM Post #15 of 16
spritzer has found a european made mil style connector that fits exactly into
the neutrik main hole with no machining whatsoever. Makes the process a whole
bunch easier when you don't have to take things completely apart to punch or
machine a new larger hole. Makes modifications to the SDS chassis completely

Unfortunately for neil, his amp is a circuit board unit, and the necessary cuts
and jumps on the board to enable the dual filament supplies is especially
painful. Complete disassembly required in this case.

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